Strap fasteners



Dec. 10,1968

(5- E. Y- HOLMBERG ET A STRAP FASTENERS 2 Sheets-Sheet. 1

Filed July 5, 1967 Q 3 m 7////9/////////// E Q 0W m4 9 9 E E D 1968 :5. E. Y. HOLMBERG ET 3,414,947

v STRAP FASTENERS 7 Filed July 5, 1967 2 Sheets-Sheet 2 K7 (@Eium United States Patent Office 3,414,947 Patented Dec. 10, 1968 3,414,947 STRAP FASTENERS Gtite Eslril Yngve Holmberg, Tokarp, Anrlerstorp, Sweden, and Josef H. Frei, Muhlestrasse 22, Ruschlikon, Switzerland Filed July 3, 1967, Ser. No. 650,969 6 Claims. (Cl. 24-196) ABSTRACT OF THE DISCLOSURE In a strap fastener for adjustable connection of a strap to a plate element such as a locking tongue or other fitting of a safety belt there is provided a linearily guided slide plate forming a bar adapted to be encircled by the strap. Between projections on the slide plate and a support fixed in relation to the plate element there is provided a bar type spring biasing the bar against an edge of an opening in said plate element to clamp the strap between the bar and the edge.

This invention relates to a strap fastener for adjustable connection of a strap to a plate element such as a looking tongue or other fitting of a safety belt for motor cars, comprising at least one bar transversely spanning an opening in said plate element and movable in its transverse direction to and from an associated edge of the opening to clamp the strap between itself and said edge, said bar being displaceable in a direction away from said edge against the action of a spring.

Such strap fasteners are widely used in connection with safety belts for motor cars because they provide a reliable fastening of the strap and simultaneously allow adjustment of the effective length of the strap by a simple motion. The strap fasteners are employed with locking tongues and buckles as well as fittings by which the safety belts are anchored in the motor car. Particularly in the case of locking tongues the strap fasteners should take up the least possible space so that the locking tongue can be given a light-Weight and slender construction not only for a pleasant appearance but also for easy and convenient handling thereof.

The invention relates to a strap fastener of the kind referred to in the foregoing, which has been developed to meet these requirements. To this end, the strap fastener is characterized in that the bar is formed by a slide plate which has a pair of opposite marginal portions movably guided in grooves provided in the plate element on one side thereof, the marginal portions of the slide plate guided in said grooves being formed with a pair of projections extending from said edge, and that the spring is a bar type spring which on one side bears against the projections with its ends and on the opposite side bears against an abutment which is stationary in relation to the plate element.

These and further features of the invention and the advantages gained thereby will appear from the following description, reference being made to the accompanying drawing in which:

FIGURE 1 is a longitudinal sectional view of an embodirnent of a locking tongue having a strap fastener in accordance with the invention;

FIGURE 2 is a plan view, partly in section, of the locking tongue in FIGURE FIGURES 3 and 4 are :orresponding views of another embodiment.

The locking tongue illustrated is a plate element with holes 11 for engagement with a cooperating locking member. The plate element 10 has angularly bent marginal portions 12 which form two parallel grooves which are open toward one another. An opening 14 is provided between the grooves in the plate element 10. A slide plate includes a bar 15 and a pair of transverse members each formed at one end of the bar and each constituting a pair of projections 16 and 17 in the plane of the bar, which extend in opposite directions. The slide plate is mova'bly guided by means of said transverse members in the grooves 13 for a plane-parallel movement transversely of the bar. A cover 18, preferably of synthetic plastics, is U-shaped in cross section and is detachably mounted on the locking tongue by means of the two flanges of the cover which grasp the angularly bent marginal portions 12 under force fit. A curved bar-type spring 20 of rectangular cross section is not much higher than the thickness of the slide plate 1517 and is mounted between the bar 15 and one flange 19 of the cover 18, the concave side of the spring facing the bar. The spring 20 on the concave side bears or is applicable against the projections 16 with its ends and on the convex side against one flange of the cover. The projections 17 restrict the movement of the bar 15 away from the spring by abutting against the other flange 19 of the cover 18.

A strap encircles the bar 15 between the projections 16 and 17, one part 21 of the strap reaching the bar from the underside of the locking tongue and after the strap has encircled the bar another part 22 thereof passes through the opening 14 between the bar and one edge 23 of the opening. At a pull at the strap part 21 the bar 15 is pulled toward the edge 23 under displacement oi the slide plate in the grooves 13, whereby the bar clamps the strap against said edge in a secure grip preventing withdrawal of the strap from the locking tongue.

As the weakest point of the strap fastener is the place where the strap is clamped between the bar and the edge 23 of the opening-ruptures primarily occur here--said edge is rounded by bending or folding (doubling) of the plate forming the plate element 10 in order to overcome said weakness, while the edge of the bar 15 facing the edge 23 is bevelled at 15, the bevelled surface merging by means of a gentle curvature with the remaining bar. The strap 21., 22 encircling the bar will thereby be formed into an S-shaped loop between tthe edges 15 and 23 of the bar 15 and the plate element 10, respectively, when a pull is effected at the strap part 21. Owing to play in the guides for the slide plate 1517 or owing to the inherent resilience of the bar 15 it may happen that the bar is raised slightly from the element 10 when it is biased against the edge 23 with the strap positioned between the edge and the bar, but this does not unfavourably affect the contemplated clamping of the strap.

The strap length is adjustable. The effective strap length is shortened by pulling at the strap part 22, and lengthened by placing the locking tongue in such a position that the plane thereof is at right angles to the longitudinal direction of the strap part 21 and effecting a pull at the locking tongue. In both cases the bar 15 is forced away from the edge 23 so that it releases its grip on the strap.

In three-point type safety belts having a hip strap and a shoulder strap it happens that the seat occupant wishes to fasten the hip strap and the shoulder strap separately in one and the same locking tongue in order to permit individual adjustment of the length of these two straps. For this purpose the embodiment shown in FIGURES 3 and 4 has been developed.

In this embodiment the plate element 10 is formed with two openings designated 14A and 14B, and the slide plate which is movably guided in grooves 13 in the plate element includes two bars designated 15A and 15B and spanning the opening 14A and 14B, respectively. The transverse members of the slide plate which interconnect the two bars at their ends are designated 17 and merge with the projections 16. In this case the spring is of circular cross section and is designated 20; in unaiased condition the spring may be straight. In order to bias the slide plate in such a sense that the bars 15A and 15B are urged against the respective associated edges 23A and 23B of the element 10, said spring 20 is interposed between the projections 16 which bear against one side of the spring at the ends thereof, and a lug 19 formed on one cover flange 19 and extending at right angles therefrom, said lug 19 bearing against the other side of the spring at the middle thereof. The two adiustably fastened straps (the hip strap and the shoulder strap in a three point safety belt for motor cars) are designated 21A, 22A and 21B, 22B respectively, and they can be lengthened and shortened in the same way as has been described in connection with the embodiment shown in FIGURES 1 and 2.

In the embodiment according to FIGURES 3 and 4 it may be suitable to bevel the bars 15A and 153 in the manner shown in FIGURE 1 and to round off the cooperating edges 23A and 23B of the element 10 by bending over said edges. Irrespective of the embodiment concerned, the spring may be of one or the other of the two types herein shown or any other generally existing kind of bar type spring. Thus the invention is nowise restricted to the embodiments described and shown, but can be modified within the scope of the appended claims.

What we claim and desire to secure by Letters Patent 1. Adjustable strap fastener comprising a plate element, means forming substantially parallel opposite guiding grooves extending along one side of said plate element, a slide plate overlying said plate element on said one side thereof and guided at opposite marginal edge portions by said guiding grooves for parallel movement in relation to said plate element, at least one bar formed by said slide plate and extending transversely between said guiding grooves, a straight edge formed by said plate element, bounding an opening therein, said edge being substantially parallel to said bar, said bar being displaceable over said opening to and from said edge by movement of said slide plate guided by said guiding grooves, projection means formed by said slide plate at said marginal edge portions thereof and extending therefrom in a direction opposite to said edge, supporting means on said plate element, and bar type spring means between said projection means and said supporting means biasing said slide plate against said edge to clamp a strap encircling said bar, between the bar and said edge.

2. A strap fastener in accordance with claim 1, wherein the grooves are formed by bent-over marginal portions of the plate element.

3. A strap fastener in accordance with claim 2, wherein the spring abutment is disposed on a cover which is mounted on the bent over marginal portions of the plate element to enclose the fastener on one side of the plate element.

4. A strap fastener in accordance with claim 3, wherein the cover is U-shaped in cross section and is mounted under force fit on the bent-over marginal portions receiving said portions between the cover flanges which extend along the bar between the bentover marginal portions, one of said flanges forming the stationary abutment for the spring.

5. A strap fastener in accordance with claim 4, wherein the bar at its ends has a pair of projections directed toward the edge surface, said projections being adapted, by engaging the other flange of the cover, to restrict the movement of the bar toward the edge of the opening.

6. A strap fastener according to claim 1, wherein said edge and the edge of the bar facing it are bevelled to clamp the strap between them in the form of a substantially S-shaped loop.

References Cited UNITED STATES PATENTS 2,938,254 5/1960 Gaylord 24-171 3,214,814 11/1965 Carter 24'196 3,343,229 9/1967 Tanaka.

BERNARD A. GELAK, Primary Examiner. 

